回复: 地球人类有史以来最震惊的访谈记录!
月亮很大,大到足以成为太阳系轨道里的一颗行星,但它却心甘情愿担当地球的卫星。不过,要是现有的太阳系行星如果成为地球的卫星,那夜晚的天空会是什么样的景象?
重新编辑,附上原文。
What if we had a planet instead of a Moon
Our moon is a pretty big object. It's big enough to be a respectable planet in its own right, if it were orbiting the sun instead of the Earth. (Actually, it
is orbiting the sun in a nearly perfectly circular orbit, that the Earth only slightly perturbs... but that's a topic for another day.) The Moon is a quarter the diameter of the Earth. Only Pluto has a satellite that is larger, in proportion to the size of the planet it orbits.
我们的月亮可真是个大家伙,如果它不是围绕地球转,而是围绕太阳转,凭借其自身的体积,它的地位肯定要比现在高。(实际上,它围绕太阳转的轨道接近于完美的圆形,只是受到地球的些许干扰。不过这不是今天的话题)月球的体积是地球的四分之一,按照这个比例,只有冥王星的卫星更大。
At a distance of about 240,000 miles, the Moon occupies a space in the night sky about half a degree wide. By sheer coincidence, this is almost exactly the same size the sun appears, which is why we occasionally get total solar eclipses. (We don't get a total eclipse every time the Moon passes in front of the sun because the Moon is sometimes a little closer to the Earth and sometimes a little further away, so it will cover more or less of the sun during any eclipse.)
月球与地球的距离约为24万英里,在夜空中占据的空间大约为0.5度。巧合的是,这和太阳看上去的尺寸正好相同,这就是为什么偶尔会发生日全食。(不是每次月球从太阳前穿过都会发生日全食,因为月球有时距地球近一些,有时远一些,所以每次日食月球遮住的面积都不一样)
But what if the Moon were size of Mars, instead? Check out how some of the other planets of the Solar System would look in our sky, if they took the Moon's place.
如果月球的体积和火星一样大会怎么样?下面的一些图片是,如果太阳系的其它行星取代月球的位置,我们在天空中将看到什么景象。
But it's interesting to imagine what the night sky might look like if one of the Solar System's planets were to replace our moon. (We'd have to ignore things like tides and gravitation, but that's the advantage of doing things in the mind's eye.) So what would we see if we were to replace the moon with Mars? The red planet is almost exactly twice the size of the Moon, so it would appear twice as big in the Earth's sky. It would be easy to see with the naked eye details on the surface of the planet that were previously visible only through telescopes. You could watch the ice caps grow and shrink during the changing seasons, see dust storms form and move across the planet and make out features like Vallis Marineris and Olympus Mons.
想象一下太阳系的其它行星取代月球位置时太空中的景象,将会非常有趣。(我们需要忽略掉潮汐和引力等问题,这些只是想象中的景象)那么,如果用火星取代月亮,我们将看到什么景象?这个红色的星球几乎是月球大小的两倍,所以它在天空中看上去将是月亮的两倍大。之前必须用望远镜才能看到的表面细节,如今裸眼就能看见。你可以在季节变化时看到火星上的冰帽形成又消融,看到尘暴在火星表面上形成并朝不同的方向移动,还可以看到火星上的水手谷及奥林匹斯山。
Venus is three and a half times larger than the Moon. It would be nearly as large in our sky as the Earth appeared to the Apollo astronauts, when they were walking on the surface of the Moon. There wouldn't be too much to see, other than vague swirling patterns in the dense, ivory-colored cloud cover. (We're pretending, of course, that Venus would still have the same atmospheric conditions if it were in essentially the same orbit as the Earth.) It would be an amazingly bright object, however much brighter than our moon. Not only does Venus reflect six times more light than the Moon, it covers an area 40 times larger... so the night skies would seem as bright as daylight.
金星是体积是月球的3.5倍。如果它取代了月球,在地球上看它,就像阿波罗宇航员看地球一样大小。不过金星上可看的就没这么多了,除了模糊的漩涡形状被象牙色的云层所覆盖(当然同样要假装金星就算位置变到了地球附近,其大气环境也不变)。然而,金星可 比月球亮多了不仅仅是因为金星可以比月球多反射6倍的光,它的表面积也比月球大40多倍...所以我们的夜晚可能会跟白天一样亮。
Neptune is more than fourteen times larger than the Moon and now we're talking about something that would look really impressive. It would loom like an enormous blue balloon in the night sky. And dominate the daytime sky, as well. All other things being equal, an eclipse of the sun would seem to last forever. Once the sun disappeared behind the edge of the "moon" earth would be plunged into darkness for over an hour and half.
海王星比月球要大14倍如果是海王星的话,那么我们到时候就会叹为观止了。它会朦胧地出现在地球的上空,就像一个突然出现的蓝色气 球。就算白天海王星也会在天上。日全食将会变成大灾难。一旦太阳消失在海王星背后,据估计,地球就会迅速投入黑暗之中,时间长达一个半小时。
Uranus, which is nearly the same size as Neptune, would provide a very similar view.
天王星由于大小和海王星类似,制造出的景象也就和海王星类似。
Saturn would be an astonishing sight. Almost 35 times larger than the Moon, this golden globe would cover nearly 18 degrees of the sky. We'd be a little further away from Saturn than its satellite Dione. In fact, we'd be more likely to be a satellite of Saturn ourselves than the other way around. The rings would stretch nearly from horizon to horizon.
土星(Saturn)出现的景象直接就让人震惊了,土星几乎比月球大35倍,在月球的位置上它大概能占据18度的天空。在这样的设定中,其实地球才更像是土星的卫星。土星的环几乎是从地平线到地平线的规模。
Jupiter would trump them all. Forty times larger than the Moon, Jupiter would stretch 20 degrees across the sky. It would also look a little different from the telescopic and spacecraft photos we're used to seeing. This close, we'd be looking "up" at the northern hemisphere and "down" at the southern hemisphere, so the cloud bands would be distinctly curved in perspective. In fact, we'd not be able to see the north and south poles of the planet.
木星可以完胜以上所有星球。土星会占据20度角的天空,它看起来也和我们之前在望远镜和航天器所拍的照片有所不同。在这么近的距离下,我们抬头就可以看到土星的北半球,低头就可以看到的是土星的南半球,所以我们也可以准确的看到弯曲的云带。不过,我们看不到土星的北极和南极。
To visualize Jupiter taking the place of our Moon, we really have to use our imaginations. Since we'd be about the same distance from Jupiter as its satellite Io, the earth would be subject to the same tidal stresses caused by Jupiter's immense gravitation. We might have a much more volcanic-looking landscape around us. There might also be little evidence for life since we'd also be in the midst of Jupiter's deadly radiation field. But as I said at the beginning, we have to make some allowances for imagination!
为了绘出让木星取代月球位置的图片,我们着实需要运用一些想象力。如果我们与木星的距离与木卫一的距离大概相同,地位就要承受木星巨大的引力引起的潮汐。我们的周围可能会出现更多的火山地貌。而且,由于处于木星致命的辐射场中,地球上可能就不太会有生命迹象。就像我在开头说的,我们必须运用一些想象力!